A transcript of that interview that was released by committee Democrats on Tuesday shows that Levy instructed Simpson to avoid discussing sources for the dossier because an unidentified person had already been killed over the salacious document.

“It’s a voluntary interview, and in addition to that he wants to be very careful to protect his sources. Somebody’s already been killed as a result of the publication of this dossier and no harm should come to anybody related to this honest work,” Levy told Jason Foster, an investigator for Senate Judiciary Committee Chairman Chuck Grassley.

Foster had asked Simpson what steps he took to assess the credibility of sources used in the dossier, which was compiled by former British spy Christopher Steele.

Fusion GPS hired Steele in Spring 2016 to investigate Donald Trump’s business activities in Russia. Fusion was working on behalf of the Clinton campaign and DNC.

It is not clear who Levy was referring to, whether he was confirming that an actual source for the dossier had been murdered, or whether he was relaying rumors that have popped up in the media over the past year.

Levy did not immediately respond to requests for comment and clarification.

There has been speculation over one death of an alleged dossier source.

Some media outlets have theorized that ex-KGB chief Oleg Erovkinin was killed because he was a source for the dossier. Erovkinin worked as chief of staff for Igor Sechin, a close ally of Vladimir Putin’s and the president of Russian oil giant Rosneft.

Sechin is alleged in the dossier to have communicated directly with Trump campaign adviser Carter Page as part of a collusion conspiracy. Page has vehemently denied the allegation and says he has never met Sechin.

Steele’s dossier uses information gleaned from close associates of Sechin’s.

If Erovkinin is who Levy was referring to, his statement to the Senate panel would seem out of whack with the circumstances of the Kremlin insider’s death.

The dossier was published to the world by BuzzFeed News on Jan. 10, 2017. Erovkinin was found dead in the back of his car on Dec. 26, 2016.

Some outlets have speculated that Russia caught wind of the dossier before it was published.